Water based epidemiology: a new wave?

<p>The screening wastewater for SARS-CoV-2 RNA has emerged in over 50 countries as a tool for tracking COVID-19 in population alongside traditional clinical monitoring, highlighting the usefulness of (waste)water-based epidemiology (WBE). Facing the significant problem of antimicrobial resistance (AMR), the monitoring of environmental AMR in epidemiologic aim is still poorly documented. As for COVID-19, WBE could be a proxy of AMR epidemiology in the context of lack of biological data i) at the community level in high income-country and ii) in lower middle-income country when resistance is often non-documented in human infections.</p><p>The aim of the study is to explore AMR from surface water running in or in the vicinity of two contrasted densely urbanized areas: Lez watershed, Montpellier, France and Djibi watershed, Abidjan, Cote d’Ivoire.</p><p>From June to November 2015, we collected 24 water samples, on 2 urban rivers in the Heart of Montpellier city: 2 sampling sites around the university hospital of Montpellier, 1 site downstream a public park and 1 site in a residential area. From July 2018 to November 2019, we collected 11 water samples in Djibi watershed (n = 11): 2 peri-urban sampling sites just outside of the Abidjan-urban area, 1 site downstream a wetland area and 1 site upstream the Aghien Lagoon.</p><p>In both cities, 100% of samples were positive for <em>bla<sub>TEM</sub></em>, an endemic beta-lactamase-encoding gene. In Montpellier, <em>bla<sub>SHV</sub></em> and <em>bla<sub>CTX-M</sub></em> were positive in 21% of samples. In Djibi watershed, 54% and 27% of samples were positive to both <em>bla<sub>SHV</sub></em> and <em>bla<sub>CTX-M</sub></em>, respectively. For carbapenemase-encoding genes which confer emerging resistance to last resort antibiotics, data were more contrasted between Montpellier and Abidjan. These genes were sparingly detected in Montpellier when the carbapenemase-encoding genes <em>bla<sub>KPC</sub>, bla<sub>NDM</sub>, bla<sub>OXA-48</sub></em> were each detected in 27% of samples in Djibi watershed samples.</p><p>The worrisome epidemiology of AMR requires to identify AMR environmental reservoirs. AMR in urban settings could represent a hot spot in the dynamics of the epidemiological cycle of AMR. The development of WBE could help to cartography AMR at a small-territory scale to help for medical decisions, alerts and implementation of preventive measures.</p>